It is well known in the prior art to fabricate wood boards, particularly for the construction of wood floors, wherein the wood boards are formed from solid wood or laminated wood which contains grooves in the back surface thereof whereby to enhance the flexibility of the boards. It is also known to fabricate wood flooring strips having small wooden slats glued to the backside thereof at regular spaced intervals to add additional flexibility to the floor board. The desired flexibility of floor boards is that they can conform to irregularities in the subfloor to which the boards are to be secured. Generally these floor boards are of thicknesses of ½ inch (12.5 mm) up to about 1 inch (25.4 mm) and provided with tongue and grooves whereby to engage one another in a side-by-side and end-to-end relationship. Such boards and the disadvantages of the related prior art are discussed for example in U.S. Pat. No. 5,283,102 issued on Feb. 1, 1994.
In recent years, laminated wood boards have become thinner with the top solid wood layer also becoming thinner normally in the range of about ⅛ inch (3.1 mm) and such laminated wood boards are installed directly on a solid wood floor or on a sound absorbing material secured to the subfloor. Transverse grooves are formed in the substrate layer of these laminated boards to provide the desired flexibility of the boards to facilitate installation thereof. However, because the top wood layer is relatively thin as compared to the substrate layer to which it is secured, the grooves formed in the substrate layer become visible in the top surface of the top wood layer by the phenomenon of telegraphy. Accordingly, the grooves need to be made very shallow and the top surface of the top wood layer is preferably of light tone or provided with a non-lustre varnish in an attempt to try to conceal the appearance or reflection of these grooves in the top surface. Therefore, laminated products have been constructed with the top wood layer having a thickness ratio in the range of one-to-one with respect to the substrate and thus affecting the flexibility of the wood board and increasing the cost thereof.